Details about the server requirements

[sfarkas1988]

Hey, thank you for your nice tool.
Using the tool with debug=true is a great help understanding why requests might fail.
But I'm missing a bit more context on the server requirements.
Testing my own gmail address is always successful.
Testing other emails mostly ends with:

[ping-email - INFO]:  SMTP Command: EHLO smtp.gmail.com
 [ping-email - INFO]:  SMTP Response: 521 5.5.1 Protocol error. Please provide the following IP address when reporting problems: 85.215.124.40
 [ping-email - INFO]:  Connection to SMTP server ended

This can have many different reasons as I understand the problem properly. My local IP is banned and that's why I can't succeed here with my local IP.
AWS does not even allow outgoing post 25 requests.
Another server I used to run projects is also creating the above error message.
But I have no idea where I should start finding out the reason to finally get successful responses.
Can you maybe add some requirements for the hosting server using your tool?

Thank you in advance.